The Response of DEM Reconstruction Algorithm on Simulating Rainfall-runoff Model

Abstract

DEM (Digital Elevation Model) as a digital expression method of regional topographic surface was widely used in various fields. In the field of hydrology, hydrological researchers also extract features based on DEM as part inputs of model. However, the accuracy and resolution of DEM directly affect the model simulation results. The objective of this study was to determine the effects of the mesh size of the digital elevation for rainfall-runoff simulation by using the physically-based surface-subsurface HydroGeoSphere model in Nanxiaohegou watershed, Xifeng city, Gansu province, China. This study firstly proposes an improved algorithm based on Poisson’s equation to reconstruct DEM. The three-scale DEM (5m,15m and 240m) is reconstructing based on the original 30m DEM using the Poisson’s method. The results show that in DEM reconstruction of decreasing scale(5m,15m), the presented method obtains a good result. Then, a rainfall-runoff simulating model of Nanxiaohegou is established, and different scales DEM(5m,15m,30m) are used to this model. Results showed that the simulated results in 15m scale DEM overmatch other scales.